draft-ietf-sacm-coswid-01.txt   draft-ietf-sacm-coswid-02.txt 
SACM Working Group H. Birkholz SACM Working Group H. Birkholz
Internet-Draft Fraunhofer SIT Internet-Draft Fraunhofer SIT
Intended status: Standards Track J. Fitzgerald-McKay Intended status: Standards Track J. Fitzgerald-McKay
Expires: August 20, 2017 Department of Defense Expires: January 5, 2018 Department of Defense
C. Schmidt C. Schmidt
The MITRE Corporation The MITRE Corporation
D. Waltermire D. Waltermire
NIST NIST
February 16, 2017 July 04, 2017
Concise Software Identifiers Concise Software Identifiers
draft-ietf-sacm-coswid-01 draft-ietf-sacm-coswid-02
Abstract Abstract
This document defines a concise representation of ISO 19770-2:2015 This document defines a concise representation of ISO 19770-2:2015
Software Identifiers (SWID tags) that is interoperable with the XML Software Identifiers (SWID tags) that is interoperable with the XML
schema definition of ISO 19770-2:2015 and augmented for application schema definition of ISO 19770-2:2015 and augmented for application
in Constrained-Node Networks. in Constrained-Node Networks. Next to the inherent capability of
SWID tags to express arbitrary context information, CoSWID support
the definition of additional semantics via well-defined data
definitions incorporated by extension points.
Status of This Memo Status of This Memo
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provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 1.1. Concise SWID Extensions . . . . . . . . . . . . . . . . . 4
2. Concise SWID CDDL specification . . . . . . . . . . . . . . . 4 1.2. Requirements Notation . . . . . . . . . . . . . . . . . . 4
3. Encoding hashes for Concise SWID tags . . . . . . . . . . . . 9 2. Concise SWID Data Definition . . . . . . . . . . . . . . . . 4
4. CoSWID used as Reference Integrity Measurements (CoSWID RIM) 9 3. Description of the SWID Attribute Vocabulary Definition . . . 9
5. Firmware SWID tags . . . . . . . . . . . . . . . . . . . . . 9 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. COSE signatures for Concise SWID tags . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. CBOR Web Token for Concise SWID tags . . . . . . . . . . . . 11 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 11 7. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 11
9. Security Considerations . . . . . . . . . . . . . . . . . . . 12 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
11. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 13 9.1. Normative References . . . . . . . . . . . . . . . . . . 12
12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 14 9.2. Informative References . . . . . . . . . . . . . . . . . 13
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 Appendix A. Explicit file-hash Type Used in Concise SWID Tags
13.1. Normative References . . . . . . . . . . . . . . . . . . 14 (label 56) . . . . . . . . . . . . . . . . . . . . . 13
13.2. Informative References . . . . . . . . . . . . . . . . . 15 Appendix B. CoSWID Attributes for Firmware (label 57) . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 Appendix C. Signed Concise SWID Tags using COSE . . . . . . . . 16
Appendix D. CoSWID used as Reference Integrity Measurements
(CoSWID RIM) . . . . . . . . . . . . . . . . . . . . 17
Appendix E. CBOR Web Token for Concise SWID Tags . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction 1. Introduction
SWID tags have several use-applications including but not limited to: SWID tags have several use-applications including but not limited to:
o Software Inventory Management, a part of the Software Asset o Software Inventory Management, a part of the Software Asset
Management [SAM] process, which requires an accurate list of Management [SAM] process, which requires an accurate list of
discernible deployed software instances. discernible deployed software components.
o Vulnerability Assessment, which requires a semantic link between o Vulnerability Assessment, which requires a semantic link between
standardized vulnerability descriptions and IT-assets [X.1520]. standardized vulnerability descriptions and IT-assets [X.1520].
o Remote Attestation, which requires a link between reference o Remote Attestation, which requires a link between reference
integrity measurements (RIM) and security logs of measured integrity measurements (RIM) and security logs of measured
software components [I-D.birkholz-tuda]. software components [I-D.birkholz-tuda].
SWID tags, as defined in ISO-19770-2:2015 [SWID], provide a SWID tags, as defined in ISO-19770-2:2015 [SWID], provide a
standardized format for a record that identifies and describes a standardized format for a record that identifies and describes a
specific release of a software product. Different software products, specific release of a software product. Different software products,
and even different releases of a particular software product, each and even different releases of a particular software product, each
have a different SWID tag record associated with them. In addition have a different SWID tag record associated with them. In addition
to defining the format of these records, ISO-19770-2:2015 defines to defining the format of these records, ISO-19770-2:2015 defines
requirements concerning the SWID tag lifecycle. Specifically, when a requirements concerning the SWID tag life-cycle. Specifically, when
software product is installed on an endpoint, that product's SWID tag a software product is installed on an endpoint, that product's SWID
is also installed. Likewise, when the product is uninstalled or tag is also installed. Likewise, when the product is uninstalled or
replaced, the SWID tag is deleted or replaced, as appropriate. As a replaced, the SWID tag is deleted or replaced, as appropriate. As a
result, ISO-19770-2:2015 describes a system wherein there is a result, ISO-19770-2:2015 describes a system wherein there is a
correspondence between the set of installed software products on an correspondence between the set of installed software products on an
endpoint, and the presence on that endpoint of the SWID tags endpoint, and the presence on that endpoint of the SWID tags
corresponding to those products. corresponding to those products.
SWID tags are meant to be flexible and able to express a broad set of SWID tags are meant to be flexible and able to express a broad set of
metadata about a software product. Moreover, there are multiple metadata about a software product. Moreover, there are multiple
types of SWID tags, each providing different types of information. types of SWID tags, each providing different types of information.
For example, a "corpus tag" is used to describe an application's For example, a "corpus tag" is used to describe an application's
installation image on an installation media, while a "patch tag" is installation image on an installation media, while a "patch tag" is
meant to describe a patch that modifies some other application. meant to describe a patch that modifies some other application.
While there are very few required fields in SWID tags, there are many While there are very few required fields in SWID tags, there are many
optional fields that support different uses of these different types optional fields that support different uses of these different types
of tags. While a SWID tag that consisted only of required fields of tags. While a SWID tag that consisted only of required fields
could be a few hundred bytes in size, a tag containing many of the could be a few hundred bytes in size, a tag containing many of the
optional fields could be many orders of magnitude larger. optional fields could be many orders of magnitude larger.
This document defines a more concise representation of SWID tags in This document defines a more concise representation of SWID tags in
the Concise Binary Object Representation (CBOR) [RFC7049]. This is the Concise Binary Object Representation (CBOR) [RFC7049]. This is
described via the CBOR Data Definition Language (CDDL) described via the Concise Data Definition Language (CDDL)
[I-D.greevenbosch-appsawg-cbor-cddl]. The resulting Concise SWID [I-D.greevenbosch-appsawg-cbor-cddl]. The resulting Concise SWID
data definition is interoperable with the XML schema definition of data definition is interoperable with the XML schema definition of
ISO-19770-2:2015 [SWID]. The vocabulary, i.e., the CDDL names of the ISO-19770-2:2015 [SWID]. The vocabulary, i.e., the CDDL names of the
types and members used in the Concise SWID data definition, is mapped types and members used in the CoSWID data definition, is mapped to
to more concise labels represented as small integers. The names used more concise labels represented as small integers. The names used in
in the CDDL and the mapping to the CBOR representation using integer the CDDL data definition and the mapping to the CBOR representation
labels is based on the vocabulary of the XML attribute and element using integer labels is based on the vocabulary of the XML attribute
names defined in ISO-19770-2:2015. and element names defined in ISO-19770-2:2015.
Real-world instances of SWID tags can be fairly large, and the Real-world instances of SWID tags can be fairly large, and the
communication of SWID tags in use-applications such as those communication of SWID tags in use-applications such as those
described earlier can cause a large amount of data to be transported. described earlier can cause a large amount of data to be transported.
This can be larger than acceptable for constrained devices and This can be larger than acceptable for constrained devices and
networks. Concise SWID tags significantly reduce the amount of data networks. CoSWID tags significantly reduce the amount of data
transported as compared to a typical SWID tag. This reduction is transported as compared to a typical SWID tag. This reduction is
enable through the use of CBOR, which maps human-readable labels of enable through the use of CBOR, which maps human-readable labels of
that content to more concise integer labels (indices). This allows that content to more concise integer labels (indices). This allows
SWID tags to be part of an enterprise security solution for a wider SWID tags to be part of an enterprise security solution for a wider
range of endpoints and environments. range of endpoints and environments.
1.1. Requirements notation 1.1. Concise SWID Extensions
This document specifies a standard equivalent to the ISO-19770-2:2015
standard. The corresponding CoSWID data definition includes two
kinds of augmentation.
o the explicit definition of types for attributes that are typically
stored in the "any attribute" of an ISO-19770-2:2015 in XML
representation. These are covered in the main body of this
document.
o the inclusion of extension points in the CoSWID data definition
that allow for additional uses of CoSWID tags that go beyond the
original scope of ISO-19770-2:2015 tags. These are covered in
appendices to this document.
1.2. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC "OPTIONAL" in this document are to be interpreted as described in RFC
2119, BCP 14 [RFC2119]. 2119, BCP 14 [RFC2119].
2. Concise SWID CDDL specification 2. Concise SWID Data Definition
The following is a CDDL representation of the ISO-19770-2:2015 [SWID] The following is a CDDL representation of the ISO-19770-2:2015 [SWID]
XML schema definition of SWID tags. This representation includes all XML schema definition of SWID tags. This representation includes
SWID tag fields and thus supports all SWID tag use cases. The every SWID tag fields and attribute and thus supports all SWID tag
CamelCase notation used in the XML schema definition is changed to use cases. The CamelCase notation used in the XML schema definition
hyphen-separated notation (e.g. ResourceCollection is named is changed to a hyphen-separated notation (e.g. ResourceCollection
resource-collection in the COSWID CDDL specification). The human- is named resource-collection in the CoSWID data definition). This
readable names of members are mapped to integer indices via a block deviation from the original notation used in the XML representation
of rules at the bottom of the CDDL specification. The 66 character reduces ambiguity when referencing certain attributes in
strings of the SWID vocabulary that would have to be stored or corresponding textual descriptions. An attribute referred by its
transported in full if using the original vocabulary are replaced. name in CamelCase notation explicitly relates to XML SWID tags, an
attribute referred by its name in hyphen-separated notation
explicitly relates to CoSWID tags. This approach simplifies the
composition of further work that reference both XML SWID and CoSWID
documents.
Human-readable names of members in the CDDL data definition are
mapped to integer indices via a block of rules at the bottom of the
definition. The 66 character strings of the SWID vocabulary that
would have to be stored or transported in full if using the original
vocabulary are replaced.
Concise Software Identifiers are tailored to be used in the domain of Concise Software Identifiers are tailored to be used in the domain of
constrained-node networks. A typical endpoint is capable of storing constrained-node networks. A typical endpoint is capable of storing
the CoSWID tag of installed software, a constrained-node might lack the CoSWID tag of installed software, a constrained-node might lack
that capability. CoSWID address these constraints and the that capability. CoSWID address these constraints and the
corresponding specification is augmented to retain their usefulness corresponding specification is augmented to retain their usefulness
in the thing-2-thing domain. Specific examples include, but are not in the thing-2-thing domain. Specific examples include, but are not
limited to limiting the scope of hash algorithms to the IANA Named limited to limiting the scope of hash algorithms to the IANA Named
Information tables or including firmware attributes addressing Information tables or including firmware attributes addressing
devices that do not necessarily provide a file-system to store a devices that do not necessarily provide a file-system to store a
CoSWID tag in. CoSWID tag in.
<CODE BEGINS> In order to create a valid CoSWID document the structure of the
concise-software-identity = { corresponding CBOR message MUST adhere to the following CDDL data
global-attributes, definition.
? entity-entry,
? evidence-entry,
? link-entry,
? software-meta-entry,
? payload-entry,
? any-element-entry,
? corpus,
? patch,
? media,
swid-name,
? supplemental,
tag-id,
? tag-version,
? version,
? version-scheme,
}
NMTOKEN = text
NMTOKENS = text
date-time = time <CODE BEGINS>
any-uri = text concise-software-identity = {
label = text / int global-attributes,
? entity-entry,
? evidence-entry,
? link-entry,
? software-meta-entry,
? payload-entry,
? any-element-entry,
? corpus,
? patch,
? media,
swid-name,
? supplemental,
tag-id,
? tag-version,
? version,
? version-scheme,
}
any-attribute = ( any-uri = text
label => text / int / [ 2* text ] / [ 2* int ] label = text / int
)
any-element-map = { any-attribute = (
global-attributes, label => text / int / [ 2* text ] / [ 2* int ]
* label => any-element-map / [ 2* any-element-map ], )
}
global-attributes = ( any-element-map = {
? lang, global-attributes,
* any-attribute, * label => any-element-map / [ 2* any-element-map ],
) }
resource-collection = ( global-attributes = (
? directory-entry, ? lang,
? file-entry, * any-attribute,
? process-entry, )
? resource-entry
? firmware-entry
)
file = { resource-collection = (
filesystem-item, ? directory-entry,
? size, ? file-entry,
? version, ? process-entry,
? file-hash, ? resource-entry
} * $$resource-extension
)
filesystem-item = ( file = {
global-attributes, filesystem-item,
? key, ? size,
? location, ? version,
fs-name, ? file-hash,
? root, }
)
directory = { filesystem-item = (
filesystem-item, global-attributes,
path-elements, ? key,
} ? location,
fs-name,
? root,
)
firmware = { directory = {
firmware-name, ; inherited from RFC4108 filesystem-item,
? firmware-version, path-elements,
? firmware-package-identifier, ; inherited from RFC4108 }
? dependency, ; inherited from RFC4108
? component-index, ; equivalent to RFC4108 fwPkgType
? block-device-identifier,
? target-hardware-identifier, ; an RFC4108 alternative to model-label
model-label,
? firmware-hash, ; a hash for a single, incl. NI hash-algo index
? cms-firmware-package, ; RCF4108, experimental, this is an actual firmware blob!
}
process = { process = {
global-attributes, global-attributes,
process-name, process-name,
? pid, ? pid,
} }
resource = { resource = {
global-attributes, global-attributes,
type, type,
} }
entity = { entity = {
global-attributes, global-attributes,
meta-elements, extended-data,
entity-name, entity-name,
? reg-id, ? reg-id,
role, role,
? thumbprint, ? thumbprint,
} }
evidence = { evidence = {
global-attributes, global-attributes,
resource-collection, resource-collection,
? date, ? date,
? device-id, ? device-id,
} }
link = { link = {
global-attributes, global-attributes,
? artifact, ? artifact,
href, href,
? media, ? media,
? ownership, ? ownership,
rel, rel,
? type, ? type,
? use, ? use,
} }
software-meta = {
global-attributes,
? activation-status,
? channel-type,
? colloquial-version,
? description,
? edition,
? entitlement-data-required,
? entitlement-key,
? generator,
? persistent-id,
? product,
? product-family,
? revision,
? summary,
? unspsc-code,
? unspsc-version,
}
payload = { software-meta = {
global-attributes, global-attributes,
resource-collection, ? activation-status,
} ? channel-type,
? colloquial-version,
? description,
? edition,
? entitlement-data-required,
? entitlement-key,
? generator,
? persistent-id,
? product,
? product-family,
? revision,
? summary,
? unspsc-code,
? unspsc-version,
}
tag-id = (0: text) payload = {
swid-name = (1: text) global-attributes,
entity-entry = (2: entity / [ 2* entity ]) resource-collection,
evidence-entry = (3: evidence / [ 2* evidence ]) }
link-entry = (4: link / [ * link ])
software-meta-entry = (5: software-meta / [ 2* software-meta ])
payload-entry = (6: payload / [ 2* payload ])
any-element-entry = (7: any-element-map / [ 2* any-element-map ])
corpus = (8: bool)
patch = (9: bool)
media = (10: text)
supplemental = (11: bool)
tag-version = (12: integer)
version = (13: text)
version-scheme = (14: NMTOKEN)
lang = (15: text)
directory-entry = (16: directory / [ 2* directory ])
file-entry = (17: file / [ 2* file ])
process-entry = (18: process / [ 2* process ])
resource-entry = (19: resource / [ 2* resource ])
size = (20: integer)
key = (21: bool)
location = (22: text)
fs-name = (23: text)
root = (24: text)
path-elements = (25: { * directory-entry,
* file-entry,
}
)
process-name = (26: text)
pid = (27: integer)
type = (28: text)
meta-elements = (29: any-element-map / [ 2* any-element-map ])
entity-name = (30: text)
reg-id = (31: any-uri)
role = (32: NMTOKENS)
thumbprint = (33: text)
date = (34: date-time)
device-id = (35: text)
artifact = (36: text)
href = (37: any-uri)
ownership = (38: "shared" / "private" / "abandon")
rel = (39: NMTOKEN)
use = (40: "optional" / "required" / "recommended")
activation-status = (41: text)
channel-type = (42: text)
colloquial-version = (43: text)
description = (44: text)
edition = (45: text)
entitlement-data-required = (46: bool)
entitlement-key = (47: text)
generator = (48: text)
persistent-id = (49: text)
product = (50: text)
product-family = (51: text)
revision = (52: text)
summary = (53: text)
unspsc-code = (54: text)
unspsc-version = (55: text)
file-hash = (56: [ hash-alg-id: int,
hash-value: bstr,
]
)
firmware-entry = (57: firmware / [ 2* firmware ]) tag-id = (0: text)
firmware-hash = (58: [ hash-alg-id: int, swid-name = (1: text)
entity-entry = (2: entity / [ 2* entity ])
evidence-entry = (3: evidence)
link-entry = (4: link / [ 2* link ])
software-meta-entry = (5: software-meta / [ 2* software-meta ])
payload-entry = (6: payload)
any-element-entry = (7: any-element-map / [ 2* any-element-map ])
corpus = (8: bool)
patch = (9: bool)
media = (10: text)
supplemental = (11: bool)
tag-version = (12: integer)
version = (13: text)
version-scheme = (14: text)
lang = (15: text)
directory-entry = (16: directory / [ 2* directory ])
file-entry = (17: file / [ 2* file ])
process-entry = (18: process / [ 2* process ])
resource-entry = (19: resource / [ 2* resource ])
size = (20: integer)
key = (21: bool)
location = (22: text)
fs-name = (23: text)
root = (24: text)
path-elements = (25: { * file-entry,
* directory-entry,
}
)
process-name = (26: text)
pid = (27: integer)
type = (28: text)
extended-data = (29: any-element-map / [ 2* any-element-map ])
entity-name = (30: text)
reg-id = (31: any-uri)
role = (32: text / [2* text])
thumbprint = (33: text)
date = (34: time)
device-id = (35: text)
artifact = (36: text)
href = (37: any-uri)
ownership = (38: "shared" / "private" / "abandon")
rel = (39: text)
use = (40: "optional" / "required" / "recommended")
activation-status = (41: text)
channel-type = (42: text)
colloquial-version = (43: text)
description = (44: text)
edition = (45: text)
entitlement-data-required = (46: bool)
entitlement-key = (47: text)
generator = (48: text)
persistent-id = (49: text)
product = (50: text)
product-family = (51: text)
revision = (52: text)
summary = (53: text)
unspsc-code = (54: text)
unspsc-version = (55: text)
file-hash = (56: [ hash-alg-id: int,
hash-value: bstr, hash-value: bstr,
] ]
) )
firmware-name = (59 : text) <CODE ENDS>
firmware-version = (60 : text / int)
component-index = (61 : int)
model-label = (62: text / int)
block-device-identifier = (63 : text / int)
cms-firmware-package = (64: bstr)
firmware-package-identifier = (65: text)
target-hardware-identifier = (66: text)
dependency = (67: { ? firmware-name,
? firmware-version,
? firmware-package-identifier,
}
)
<CODE ENDS>
3. Encoding hashes for Concise SWID tags
Concise SWID add explicit support for the representation of file-
hashes using algorithms that are registered at the Named Information
Hash Algorithm Registry via the file-hash item (label 56). The
number used as a value for hash-alg-id refers the ID in the Named
Information Hash Algorithm table.
4. CoSWID used as Reference Integrity Measurements (CoSWID RIM)
A vendor supplied signed CoSWID tag that includes hash-values for the
files that compose a software component can be used as a RIM
(reference integrity measurement). A RIM is a type of declarative
guidance that can be used to assert the compliance of an endpoint by
assessing the installed software. In the context of remote
attestation based on an attestation via a hardware security module
(hardware rooted trust), a verifier can appraise the integrity of the
conveyed measurements of software components using a CoSWID RIM
provided by a source, such as
[I-D.banghart-sacm-rolie-softwaredescriptor].
5. Firmware SWID tags
The metadata defined in [RFC4108] is incorporated in the resource-
collection structure that semantically differentiates content stored
in a Concise Software Identifier. The optional attributes that
annoate a firmware package addresse specific characteristics of
pieces of firmware stored directly on a block-device in contrast to
software deployed in a file-system. Trees of relative path-elements
expressed by the directory and file structure in CoSWID tags are
typically unable to represent the location of a firmware on a
constrained-node (small thing). The composite nature of firmware and
also the actual composition of small things require a set of
attributes to identify the correct component in a composite thing for
each individual piece of firmware. A single component also
potentially requires a number of distinct firmware parts that might
depend on each other(s version). These dependencies can be limited
to the scope of the component itself or extend to the scope of a
small composite device. In addition, it might not be possible (or
feasible) to store a CoSWID tag document (permanently) on a small
thing along with the corresponding piece of firmware. Hence, CoSWID
tags can be used as a concise and flexible metadata document that
functions as a wrapper containing a (potentially compressed, signed,
and/or encrypted) piece of firmware and its corresponding CoSWID
attributes. A CoSWID tag about firmware can be transmitted as an
identifying document across endpoints or used as an reference
integrity measurement as usual. Alternatively, it can also convey an
actual piece of firmware, serve its intended purpose as a SWID tag
and then - due to the lack of a location to store it - be discarded.
6. COSE signatures for Concise SWID tags
SWID tags, as defined in the ISO-19770-2:2015 XML schema, can include
cryptographic signatures to protect the integrity of the SWID tag.
In general, tags are signed by the tag creator (typically, although
not exclusively, the vendor of the software product that the SWID tag
identifies). Cryptographic signatures can make any modification of
the tag detectable, which is especially important if the integrity of
the tag is important, such as when the tag is providing golden
measurements for files.
The ISO-19770-2:2015 XML schema uses XML DSIG to support
cryptographic signatures. Concise SWID tags require a different
signature scheme than this. COSE (CBOR Encoded Message Syntax)
provides the required mechanism [I-D.ietf-cose-msg]. Concise SWID
can be wrapped in a COSE Single Signer Data Object (cose-sign1) that
contains a single signature. The following CDDL defines a more
restrictive subset of header attributes allowed by COSE tailored to
suit the requirements of Concise SWID.
<CODE BEGINS>
signed-coswid = #6.997(COSE-Sign1-coswid) ; see TBS7 in current COSE I-D
label = int / tstr ; see COSE I-D 1.4.
values = any ; see COSE I-D 1.4.
unprotected-signed-coswid-header = {
1 => int, ; algorithm identifier
3 => "application/coswid", ; request for CoAP IANA registry to become an int
* label => values,
}
protected-signed-coswid-header = {
4 => bstr, ; key identifier
* label => values,
}
COSE-Sign1-coswid = [
protected: bstr .cbor protected-signed-coswid-header,
unprotected: unprotected-signed-coswid-header,
payload: bstr .cbor concise-software-identity,
signature: bstr,
]
<CODE ENDS>
7. CBOR Web Token for Concise SWID tags
A typical requirement regarding specific instantiations of endpoints 3. Description of the SWID Attribute Vocabulary Definition
- and, as a result, specific instantiations of software components -
is a representation of the absolute path of a CoSWID tag document in
a file system in order to derive absolute paths of files represented
in the corresponding CoSWID tag. The absolute path of an evidence
CoSWID tag can be included as a claim in the header of a CBOR Web
Token [I-D.ietf-ace-cbor-web-token]. Depending on the source of the
token, the claim can be in the protected or unprotected header
portion.
<CODE BEGINS> Yet to be written still...
CDDL TBD
<CODE ENDS>
8. IANA considerations 4. IANA Considerations
This document will include requests to IANA: This document will include requests to IANA:
o Integer indices for SWID content attributes and information o Integer indices for SWID content attributes and information
elements. elements.
o Content-Type for CoAP to be used in COSE. o Content-Type for CoAP to be used in COSE.
9. Security Considerations 5. Security Considerations
SWID tags contain public information about software products and, as SWID tags contain public information about software products and, as
such, do not need to be protected against disclosure on an endpoint. such, do not need to be protected against disclosure on an endpoint.
Similarly, SWID tags are intended to be easily discoverable by Similarly, SWID tags are intended to be easily discoverable by
applications and users on an endpoint in order to make it easy to applications and users on an endpoint in order to make it easy to
identify and collect all of an endpoint's SWID tags. As such, any identify and collect all of an endpoint's SWID tags. As such, any
security considerations regarding SWID tags focus on the application security considerations regarding SWID tags focus on the application
of SWID tags to address security challenges, and the possible of SWID tags to address security challenges, and the possible
disclosure of the results of those applications. disclosure of the results of those applications.
skipping to change at page 13, line 28 skipping to change at page 11, line 7
Concise SWID data definition allow for the construction of "infinite" Concise SWID data definition allow for the construction of "infinite"
SWID tags or SWID tags that contain malicious content with the intend SWID tags or SWID tags that contain malicious content with the intend
if creating non-deterministic states during validation or processing if creating non-deterministic states during validation or processing
of SWID tags. While software product vendors are unlikely to do of SWID tags. While software product vendors are unlikely to do
this, SWID tags can be created by any party and the SWID tags this, SWID tags can be created by any party and the SWID tags
collected from an endpoint could contain a mixture of vendor and non- collected from an endpoint could contain a mixture of vendor and non-
vendor created tags. For this reason, tools that consume SWID tags vendor created tags. For this reason, tools that consume SWID tags
ought to treat the tag contents as potentially malicious and should ought to treat the tag contents as potentially malicious and should
employ input sanitizing on the tags they ingest. employ input sanitizing on the tags they ingest.
10. Acknowledgements 6. Acknowledgements
11. Change Log 7. Change Log
Changes from version 00 to version 01: Changes from version 00 to version 01:
o Added CWT usage for absolute SWID paths on a device o Added CWT usage for absolute SWID paths on a device
o Fixed cardinality of type-choices including arrays o Fixed cardinality of type-choices including arrays
o Included first iteration of firmware resource-collection o Included first iteration of firmware resource-collection
Changes since adopted as a WG I-D -00: Changes since adopted as a WG I-D -00:
skipping to change at page 14, line 4 skipping to change at page 11, line 31
o Removed redundant any-attributes originating from the ISO- o Removed redundant any-attributes originating from the ISO-
19770-2:2015 XML schema definition 19770-2:2015 XML schema definition
o Fixed broken multi-map members o Fixed broken multi-map members
o Introduced a more restrictive item (any-element-map) to represent o Introduced a more restrictive item (any-element-map) to represent
custom maps, increased restriction on types for the any-attribute, custom maps, increased restriction on types for the any-attribute,
accordingly accordingly
o Fixed X.1520 reference o Fixed X.1520 reference
o Minor type changes of some attributes (e.g. NMTOKENS) o Minor type changes of some attributes (e.g. NMTOKENS)
o Added semantic differentiation of various name types (e,g. fs- o Added semantic differentiation of various name types (e,g. fs-
name) name)
Changes from version 00 to version 01: Changes from version 00 to version 01:
o Ambiguity between evidence and payload eliminated by introducing o Ambiguity between evidence and payload eliminated by introducing
explicit members (while still allowing for "empty" swid tags) explicit members (while still
o allowing for "empty" SWID tags)
o Added a relatively restrictive COSE envelope using cose_sign1 to o Added a relatively restrictive COSE envelope using cose_sign1 to
define signed coswids (single signer only, at the moment) define signed CoSWID (single signer only, at the moment)
o Added a defintion how to encode hashes that can be stored in the o Added a definition how to encode hashes that can be stored in the
any-member using existing IANA tables to reference hash-algorithms any-member using existing IANA tables to reference hash-algorithms
First version -00 Changes from version 01 to version 02:
12. Contributors o Enforced a more strict separation between the core CoSWID
definition and additional usage by moving content to corresponding
appendices.
13. References o Removed artifacts inherited from the reference schema provided by
ISO (e.g. NMTOKEN(S))
13.1. Normative References o Simplified the core data definition by removing group and type
choices where possible
o Minor reordering of map members
o Added a first extension point to address requested flexibility for
extensions beyond the any-element
8. Contributors
9. References
9.1. Normative References
[I-D.ietf-ace-cbor-web-token] [I-D.ietf-ace-cbor-web-token]
Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig, Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig,
"CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-02 "CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-07
(work in progress), January 2017. (work in progress), July 2017.
[I-D.ietf-cose-msg] [I-D.ietf-cose-msg]
Schaad, J., "CBOR Object Signing and Encryption (COSE)", Schaad, J., "CBOR Object Signing and Encryption (COSE)",
draft-ietf-cose-msg-24 (work in progress), November 2016. draft-ietf-cose-msg-24 (work in progress), November 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC4108] Housley, R., "Using Cryptographic Message Syntax (CMS) to [RFC4108] Housley, R., "Using Cryptographic Message Syntax (CMS) to
Protect Firmware Packages", RFC 4108, Protect Firmware Packages", RFC 4108,
DOI 10.17487/RFC4108, August 2005, DOI 10.17487/RFC4108, August 2005,
<http://www.rfc-editor.org/info/rfc4108>. <http://www.rfc-editor.org/info/rfc4108>.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
<http://www.rfc-editor.org/info/rfc4949>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <http://www.rfc-editor.org/info/rfc7049>. October 2013, <http://www.rfc-editor.org/info/rfc7049>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<http://www.rfc-editor.org/info/rfc7228>.
[SAM] "Information technology - Software asset management - Part [SAM] "Information technology - Software asset management - Part
5: Overview and vocabulary", ISO/IEC 19770-5:2013, 5: Overview and vocabulary", ISO/IEC 19770-5:2013,
November 2013. November 2013.
[SWID] "Information technology - Software asset management - Part [SWID] "Information technology - Software asset management - Part
2: Software identification tag'", ISO/IEC 19770-2:2015, 2: Software identification tag'", ISO/IEC 19770-2:2015,
October 2015. October 2015.
[X.1520] "Recommendation ITU-T X.1520 (2014), Common [X.1520] "Recommendation ITU-T X.1520 (2014), Common
vulnerabilities and exposures", April 2011. vulnerabilities and exposures", April 2011.
13.2. Informative References 9.2. Informative References
[I-D.banghart-sacm-rolie-softwaredescriptor] [I-D.banghart-sacm-rolie-softwaredescriptor]
Waltermire, D. and S. Banghart, "Definition of the ROLIE Waltermire, D. and S. Banghart, "Definition of the ROLIE
Software Descriptor Extension", draft-banghart-sacm-rolie- Software Descriptor Extension", draft-banghart-sacm-rolie-
softwaredescriptor-00 (work in progress), October 2016. softwaredescriptor-01 (work in progress), May 2017.
[I-D.birkholz-tuda] [I-D.birkholz-tuda]
Fuchs, A., Birkholz, H., McDonald, I., and C. Bormann, Fuchs, A., Birkholz, H., McDonald, I., and C. Bormann,
"Time-Based Uni-Directional Attestation", draft-birkholz- "Time-Based Uni-Directional Attestation", draft-birkholz-
tuda-03 (work in progress), January 2017. tuda-04 (work in progress), March 2017.
[I-D.greevenbosch-appsawg-cbor-cddl] [I-D.greevenbosch-appsawg-cbor-cddl]
Vigano, C. and H. Birkholz, "CBOR data definition language Birkholz, H., Vigano, C., and C. Bormann, "CBOR data
(CDDL): a notational convention to express CBOR data definition language (CDDL): a notational convention to
structures", draft-greevenbosch-appsawg-cbor-cddl-09 (work express CBOR data structures", draft-greevenbosch-appsawg-
in progress), September 2016. cbor-cddl-10 (work in progress), March 2017.
[I-D.ietf-sacm-terminology]
Birkholz, H., Lu, J., Strassner, J., and N. Cam-Winget,
"Security Automation and Continuous Monitoring (SACM)
Terminology", draft-ietf-sacm-terminology-12 (work in
progress), March 2017.
Appendix A. Explicit file-hash Type Used in Concise SWID Tags (label
56)
CoSWID add explicit support for the representation of file-hashes
using algorithms that are registered at the Named Information Hash
Algorithm Registry via the file-hash member (label 56).
file-hash = (56: [ hash-alg-id: int, hash-value: bstr ] )
The number used as a value for hash-alg-id MUST refer the ID in the
Named Information Hash Algorithm table; other hash algorithms MUST
NOT be used. The hash-value MUST represent the raw hash value of the
file-entry the file-hash type is included in.
Appendix B. CoSWID Attributes for Firmware (label 57)
The ISO-19770-2:2015 specification of SWID tags assumes the existence
of a file system a software component is installed and stored in. In
the case of constrained-node networks [RFC7228] or network equipment
this assumption might not apply. Concise software instances in the
form of (modular) firmware are often stored directly on a block
device that is a hardware component of the constrained-node or
network equipment. Multiple differentiable block devices or
segmented block devices that contain parts of modular firmware
components (potentially each with their own instance version) are
already common at the time of this writing.
The optional attributes that annotate a firmware package address
specific characteristics of pieces of firmware stored directly on a
block-device in contrast to software deployed in a file-system. In
essence, trees of relative path-elements expressed by the directory
and file structure in CoSWID tags are typically unable to represent
the location of a firmware on a constrained-node (small thing). The
composite nature of firmware and also the actual composition of small
things require a set of attributes to address the identification of
the correct component in a composite thing for each individual piece
of firmware. A single component also potentially requires a number
of distinct firmware parts that might depend on each other
(versions). These dependencies can be limited to the scope of the
component itself or extend to the scope of a larger composite device.
In addition, it might not be possible (or feasible) to store a CoSWID
tag document (permanently) on a small thing along with the
corresponding piece of firmware.
To address the specific characteristics of firmware, the extension
point "$$resource-extension" is used to allow for an additional type
of resource description--firmware-entry--thereby increasing the self-
descriptiveness and flexibility of CoSWID. The optional use of the
extension point "$$resource-extension" in respect to firmware MUST
adhere to the following CDDL data definition.
<CODE BEGINS>
$$resource-extension //= (firmware-entry,)
firmware = {
firmware-name, ; inherited from RFC4108
? firmware-version,
? firmware-package-identifier, ; inherited from RFC4108
? dependency, ; inherited from RFC4108
? component-index, ; equivalent to RFC4108 fwPkgType
? block-device-identifier,
? target-hardware-identifier, ; an RFC4108 alternative to model-label
model-label,
? firmware-hash, ; a hash for a single, incl. NI hash-algo index
? cms-firmware-package, ; RCF4108, experimental, this is an actual firmware blob!
}
firmware-entry = (57: firmware / [ 2* firmware ])
firmware-hash = (58: [ hash-alg-id: int,
hash-value: bstr,
]
)
firmware-name = (59 : text)
firmware-version = (60 : text / int)
component-index = (61 : int)
model-label = (62: text / int)
block-device-identifier = (63 : text / int)
cms-firmware-package = (64: bstr)
firmware-package-identifier = (65: text)
target-hardware-identifier = (66: text)
dependency = (67: { ? firmware-name,
? firmware-version,
? firmware-package-identifier,
}
)
<CODE ENDS>
The members of the firmware group that constitutes the content of the
firmware-entry is based on the metadata about firmware defined in
[RFC4108]. As with every semantic differentiation that is supported
by the resource-collection type, the use of firmware-entry is
optional. It is REQUIRED not to instantiate more than one firmware-
entry, as the firmware group is used in a map and therefore only
allows for unique labels.
The optional cms-firmware-package member allows to include the actual
firmware in the CoSWID tag that also expresses its metadata as a
byte-string. This option enables a CoSWID tag to be used as a
container or wrapper that composes both firmware and its metadata in
a single document (which again can be signed, encrypted and/or
compressed). In consequence, a CoSWID tag about firmware can be
conveyed as an identifying document across endpoints or used as a
reference integrity measurement as usual. Alternatively, it can also
convey an actual piece of firmware, serve its intended purpose as a
SWID tag and then - due to the lack of a location to store it - be
discarded.
Appendix C. Signed Concise SWID Tags using COSE
SWID tags, as defined in the ISO-19770-2:2015 XML schema, can include
cryptographic signatures to protect the integrity of the SWID tag.
In general, tags are signed by the tag creator (typically, although
not exclusively, the vendor of the software product that the SWID tag
identifies). Cryptographic signatures can make any modification of
the tag detectable, which is especially important if the integrity of
the tag is important, such as when the tag is providing reference
integrity measurments for files.
The ISO-19770-2:2015 XML schema uses XML DSIG to support
cryptographic signatures. CoSWID tags require a different signature
scheme than this. COSE (CBOR Object Signing and Encryption) provides
the required mechanism [I-D.ietf-cose-msg]. Concise SWID can be
wrapped in a COSE Single Signer Data Object (cose-sign1) that
contains a single signature. The following CDDL defines a more
restrictive subset of header attributes allowed by COSE tailored to
suit the requirements of Concise SWID.
<CODE BEGINS>
signed-coswid = #6.997(COSE-Sign1-coswid) ; see TBS7 in current COSE I-D
label = int / tstr ; see COSE I-D 1.4.
values = any ; see COSE I-D 1.4.
unprotected-signed-coswid-header = {
1 => int, ; algorithm identifier
3 => "application/coswid", ; request for CoAP IANA registry to become an int
* label => values,
}
protected-signed-coswid-header = {
4 => bstr, ; key identifier
* label => values,
}
COSE-Sign1-coswid = [
protected: bstr .cbor protected-signed-coswid-header,
unprotected: unprotected-signed-coswid-header,
payload: bstr .cbor concise-software-identity,
signature: bstr,
]
<CODE ENDS>
Appendix D. CoSWID used as Reference Integrity Measurements (CoSWID
RIM)
A vendor supplied signed CoSWID tag that includes hash-values for the
files that compose a software component can be used as a RIM
(reference integrity measurement). A RIM is a type of declarative
guidance that can be used to assert the compliance of an endpoint by
assessing the installed software. In the context of remote
attestation based on an attestation via hardware rooted trust, a
verifier can appraise the integrity of the conveyed measurements of
software components using a CoSWID RIM provided by a source, such as
[I-D.banghart-sacm-rolie-softwaredescriptor].
RIM Manifests (RIMM): A group of SWID tags about the same
(sub-)system, system entity, or (sub-)component (compare
[RFC4949]). A RIMM manifest is a distinct document that is
typically conveyed en-block and constitutes declarative guidance
in respect to a specific (target) endpoint (compare
[I-D.ietf-sacm-terminology]).
If multiple CoSWID compose a RIMM, the following CDDL data definition
SHOULD be used.
RIMM = [ + concise-software-identity / signed-coswid ]
Appendix E. CBOR Web Token for Concise SWID Tags
A typical requirement regarding specific instantiations of endpoints
- and, as a result, specific instantiations of software components -
is a representation of the absolute path of a CoSWID tag document in
a file system in order to derive absolute paths of files represented
in the corresponding CoSWID tag. The absolute path of an evidence
CoSWID tag can be included as a claim in the header of a CBOR Web
Token [I-D.ietf-ace-cbor-web-token]. Depending on the source of the
token, the claim can be in the protected or unprotected header
portion.
<CODE BEGINS>
CDDL TBD
<CODE ENDS>
Authors' Addresses Authors' Addresses
Henk Birkholz Henk Birkholz
Fraunhofer SIT Fraunhofer SIT
Rheinstrasse 75 Rheinstrasse 75
Darmstadt 64295 Darmstadt 64295
Germany Germany
Email: henk.birkholz@sit.fraunhofer.de Email: henk.birkholz@sit.fraunhofer.de
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